quick question, during some of the events with lindsey, (for example her falling over) how do u unlock the choices that have the weird blue picture of lindsey's face?
That blue faced icon means you have to be on the Lindsey "Hate" route to use that particular interaction. If you want to access it you need to be an absolute monster to her every time you interact with her. It doesn't matter if you go Isabelle or Kate.
During "Day 1, Take 2" when Lindsey trips on the wet floor sign choose to enjoy the view
Then during "Loser to the Rescue" when Lindsey crashes into you in the gym say "She should've paid more attention." and then "Pass"
Once you have finished "Tour de School" and Lindsey becomes available to interact with again Quest her and say "Well, suck it up, princess. Life's not a bed of roses."
This will permanently lock you into the Lindsey "Hate" route. There isn't too much in it as of v1.44.1 and a fair number of interactions don't reflect your actions toward her at all. Who knows what the future holds though.